The New York morning of September 11, 2001, continues to dictate world events to this day. It was the moment the globe looked on in horror, with daily routines stopped in their tracks. After a slight delay, even the closeted world of football had to look up and take notice after the World Trade Center was razed to the ground and the Pentagon wrecked by Al-Qaeda's attack.

One of football's most overused cliches is that 'things' are put into perspective by a real-life event. The question of when perspective was actually lost is always a pertinent one but, following the supernaturally horrific scenes in New York and Washington DC, it was understandable that the game took time to find its bearings.

Over in Europe, the ramifications of what had happened took time to digest, and the Tuesday evening of September 11 saw a full programme of matches played, including in the Champions League.

The time difference between Europe and the United States - the events began in the early afternoon in Europe - meant that teams playing in the competition were already in situ to play. The blanket flight bans that took hold soon after the world became aware that this was an act of terror rather than an accident had not hampered any team's participation. With the inflexibility of the European football calendar in mind, football continued in normal if distracted fashion.

Arsenal were at Real Mallorca and their campaign began in miserable fashion as a youthful Ashley Cole was dismissed after just 11 minutes for a foul on Alberto Luque to concede the Vicente Engonga penalty that won the game. At Anfield, meanwhile, a Gerard Houllier-led Liverpool played out a stagnant 1-1 draw with Boavista.

A one-minute silence had been observed before the Champions League and UEFA Cup matches on the Tuesday night as a mark of respect for the victims. Gerhard Aigner, the chief executive of European football's governing body, said in a statement: "UEFA wishes to express its profound sadness and horror at the tragic and terrible events which have taken place today in the United States. Our thoughts and hearts go out to all the victims of these dreadful attacks and our sincerest sympathy to their families and friends."

By the following day, the world was on full terror alert, with aftershocks rippling around the globe. As extra vigilance took hold, many a false alarm was rung, and it became apparent that life would not be continuing as normal for the foreseeable future.

To prevent situations of panic, risk was all but abandoned and Wednesday morning saw UEFA decide to postpone the rest of that week's fixtures. "The scale of this tragedy and the pain and sorrow which it brings should cause us all to reflect," Aigner said. "UEFA feels it is right that the European football family should respect the loss and suffering."

Manchester United were already in Greece awaiting their Group G opener against Olympiakos, and would have to wait until October 10 to play the match. It was a decision not greeted with enthusiasm by the host club. "We are very, very upset. This cancellation changes all our plans," Olympiakos spokeswoman Olga Nikolaidou told Reuters.

However, Kim Milton Nielsen, who had been set to referee the game, said: "Football is nothing.

"It's very difficult to say if it is the right decision. You can have an opinion both ways. Of course, it's very bad that terrorists have shown how they can stop football in the whole of Europe [but] football is small where more than 10,000 people have been killed." At this point, the death toll, with so many missing and unaccounted for, was unknown and would prove to be far less than was widely quoted on that Wednesday.

Fiorentina chief executive Luciano Luna, whose team were to play Dnipro Dnipropetrovsk in the UEFA Cup on the Thursday, said the postponement decision was right - but had come a day late. "It was a decision of good sense - which should have been taken yesterday," he said. His was not to be the only voice of such dissent.

PSV Eindhoven had been beaten 4-1 in Nantes on Tuesday and the Dutch club asked UEFA to order a replay, citing the distraction of a team who had sat in their French hotel watching the horror enfold. "We," defender Kevin Hofland told the Daily Telegraph, "felt like mourners at a funeral. And when we got to the stadium, it provided the same odd contrast with our emotions - the place was like a disco! Their players were really up for it too, while we just couldn't concentrate. It was strange - as if they didn't have television in Nantes."

PSV's Belgian coach, Eric Gerets, had called his players together and asked if anyone wanted the night off and, while none demurred, their club felt they had a case, though this was swiftly to be nixed by the governing body.

Another player who played on the Tuesday was Liverpool's Gary McAllister. He had spent his pre-match afternoon glued to TV rolling news with room-mate Nick Barmby. "I don't feel it affected me so much once the game had got underway. Maybe the vastness had yet to register," he said the following weekend. "I don't think I'd have wanted to play on Wednesday or Thursday. The full significance had sunk in - and there was a need to show respect."

Houllier, while offering no excuses for drawing with Boavista, summed up his view of the football that did take place on Tuesday: "If you don't have that drive and desire to win the game, there is not much point in playing. At the end of the night, a journalist wrote that a draw was the right result because no one would have wanted to celebrate. I agreed with that. No one had the heart to celebrate."

Sadly, there were those who did show a lack of perspective. Chelsea's UEFA Cup home match with Levski Sofia was called off, leaving Frank Lampard, John Terry, Jody Morris and Eidur Gudjohnsen at a loose end they decided to fill with an extended drinking session that eventually ended up at a Heathrow hotel. There, the booze-sodden quartet's antics offended a group of grieving American tourists stuck in the UK because of the flight ban and, not for the last time, converted themselves into tabloid pariahs.

By the weekend of September 15 and 16, with minutes' silences observed and black armbands worn, football continued on as normal, but in a world that has never been the same since.

What happened next? Having lost their appeal, PSV exited the Champions League in the first group stage while Nantes progressed to face Manchester United in the second group stage that was part of the competition at that time. Real Madrid would win the competition that year. Frank Lampard scored during his team's ill-tempered defeat of Tottenham, while Liverpool enjoyed Merseyside derby success against Everton and Manchester United lost 4-3 at Newcastle United. Football has often been mentioned as a terror target since, though thankfully no such major occurrence has yet resulted.